Along with the development of economy and technology, people's awareness and attitudes to the society and the environment have been changed, and bicycles are becoming an important part of people's life.
As for a bicycle, the maintenance of tires is very important, which is often ignored by people. The air pressure in the tire is found to be too low in cycling, which will affect the speed of the bicycle and will go against the maintenance of tires. So the portable pump is becoming more and more popular among bicycle enthusiasts.
The pump with single barrel in the prior art is the one with a long stroke. This kind of pump is detachable and can be installed on the frame of the bicycle, but the big size of it affects the use of the bicycle.
Another kind of miniature pump has a shorter stroke than the pump with single barrel. It can be removed from the bicycle conveniently and doesn't affect the use of the bicycle, but the amount of air pumped in one stroke is small due to the short stroke of the pump.
Chinese patent application NO. 200480041170.9 discloses a pump, which solves the two incompatible problems described above. The defects of the pump are that the foldable foot stand is apt to knock the rear frame assembly, and it is not easy to take out the connector and fix it on the valve of the tire.